Trigger

A Trigger (トリガー Torigā), as the name implies, is a condition that initiates Magic (or a Spell) once met.

Types

Four types of Triggers are recognised in Magical Girl Lyrical Nanoha/A's Visual Fan Book:

Aria (詠唱 Eishō)

A long incantation, usually required for complex Magic or powerful Spells. Arias often include a Mage's personal incantation, such as Nanoha Takamachi's "Lyrical! Magical!" Reinforce, and later Hayate Yagami, require Arias for most of their Spells even when less powerful Mages do not.

Command (コマンド Komando)

A short command phrase, also known as Trigger Code (トリガーコード Torigā Kōdo). For example, Fate Testarossa's command phrase for her shooting skills is "Fire!" In cases where a Mage does not need an incantation to activate a skill, the Device may bark the Command in its master's stead.

Action Trigger (アクショントリガー Akushon Torigā)

A motion, usually a distinctive swing of the Device, or a finger snap. Action Triggers usually accompany command phrases.

Device Activation (デバイス発動 Debaisu Hatsudō)

The autonomous activation sequence by an Intelligent Device. This usually happens when the user is in danger from an incoming attack (e.g. Auto Guard, Mach Caliber's Caliber Shot). Depending on the skill or talent of the user, this may require a complex passphrase.

Follow-up command phrases

Other than the command to initiate a Spell, there are also command phrases to follow up with Spells for different purposes.

Snip Shot is a notable one over the series for speeding up projectiles of shooting attacks.

Besides, "... End" has also been used as a command phrase for the finish blow of Ranged Spells:

• Spark End (Photon Lancer Phalanx Shift, The MOVIE 1st)
• Heat End (Luciferion Breaker, Reflection)
• Burst End (Starlight Breaker, Reflection)